The overall aims are to define the basic effects of gonadal steroids, the effects of patterns of gonadal steroids, and the interactions of seasonal effects and gonadal steroids on LHRH and LH patterns in the male using the ram as a model. The specific aims are: 1. To define the effect of season on LHRH and LH pulse relationships and test the null hypotheses that LHRH secretory patterns and LHRH-LH relationships do not change with season. LHRH and LH pulse parameters will be analyzed at 3 phases of the annual reproductive cycle. 2. To test the null hypothesis that the major gonadal steroids (testosterone and estrogen) do not alter LHRH pulse parameters in the male. The effects of constant physiological concentrations of testosterone and estrogen, alone and combined, on LH and LHRH pulse parameters will be determined. 3. To test the hypothesis that episodic delivery of testosterone is more effective in altering LHRH and LH pulse parameters than is constant delivery. The effects of the two modes of delivery will be compared. 4. To test the hypothesis that the pattern of testosterone pulses affects the patterns of LHRH and LH pulses. Initially, the effects of symmetrical, evenly spaced T pulses will be compared with the effects of symmetrical, unevenly spaced T pulses.